Biological fluids like blood plasma or serum, milk, whey, urine, etc. contain a mixture of several proteins. For example, blood plasma contains albumin (3.5-4.5 g/100 ml), fibrinogen (0.20-0.45 g/100 ml), .alpha.-globulins (0.4-1.0 g/100 ml), .beta.-globulins (0.8 g/100 ml), immunoglobulin-IgG (0.8-1.8 g/100 ml), IgD (0.015 g/100 ml), IgA (0.09-0.45 g/100 ml), IgM (0.06-0.25 g/100 ml), etc. (Frank W. Putnam, The Trace Components of Plasma, An Overview). The immunoglobulins (Ig) are very important since they are involved in the proctective and defensive mechanism against infectious organisms. Clinical diseases characterized by imbalances of these systems of proteins, either in the ability to recognize invading mechanism or to recognize one's self, have promoted the basic understanding of the clinical aspects of the science of immunity. Abnormal immunological reactions are now known to cause a wide spectrum of diseases. Examples of diseases known to be associated with immune complex reactions include, for example, serum sickness, glomerulonephritis and myasthenia gravis. Plasmapheresis is a technique used to curtain, favorably interfere with or stop the immunopathologic process associated with circulating humoral antibody and/or immune complexes of the plasma. [Glassman, Rationale for Plasmapheresis, "Plasma Thereapy", Vol. 1 , Page 13 (1979)].
A known method is to plasmapherese about 4 liters of plasma over a period of 2-4 hours. The plasma removed from the patient is usually discarded and replaced by albumin and either physiological saline or Ringer's solution to make up the protein, electrolyte, and water balance. This is an expensive method and sometimes also leaves the patient in a hypoimmune state. In another method the make up of the removed plasma is accomplished by giving fresh frozen plasma, and though less expensive, suffers from the risk of transmitting hepatitis virus to the patient. The method of the present invention overcomes these problems by selectively removing euglobulins or euglobulin antigen complexes causing or resulting from the disease and at the same time restoring the major portions of albumin, electrolyte (salt) and water and thus returning to the patient his or her own plasma (without IgG-antigen) containing the proper protein, salt, and water balance. This technique makes the exchange less expensive and risk free from hepatitis since no additional albumin, salt, water or donor plasma is required. The present invention will be described using serum proteins as the principal example but the scope of this invention can also be applied to other biological fluids or other proteins without limiting the scope of the invention.
The present method thus generates a product capable of being used is situ without any additional modification of salt, protein or water content whereas the product of the prior art (Brown, U.S. Pat. No. 3,579,441) requires a make up of salts and water before any administration of the proteins back to the patient can be made and (Stern, 3,972,791) which requires cold (below 15.degree. C.) processing and further purification steps.